Backing-off attachment for lathes.



T. MELDER.

, BACKING OFF ATTACHMENTFOR LATHES' I APPLLCATION FILED JAN- 4 1917. 1 ,251,263. Patented Bea-25,1917.

2 SHEETS-SHEET 1.

Inventor:

T. mum. BACKING OFF ATTACHMENT FOR LATHESV APPLICATION FIL ED IAN.4, I917.

1,251,2889 I "Patented De0.25,1917;

2 SHEETS-SHEET 2.

THEODORE MELDER 0F DEDHAM, MASSACHUSETTS.

BACKING-OFF ATTACHMENT FOR LATHES.

Specification of Letters Patent. Patented Dec. 25, 1917.

Application filed January 4, 1917. Serial No. 140,485.

To all whom it may concern.

Be it known that I, THEODORE MELDER, a citizen of the United States, residing at Dedham, in the county of Norfolk and State of Massachusetts, have invented new and useful Improvements in Backing-Off Attachments for Lathes, of which the following is a specification.

This invention relates to improvements in backing ofi' attachments for lathes or similar machines and has for itsobject to provide a simple and accurate device for reproducing teeth of various forms, as may be represented by a pattern, upon the work to form milling cutters, hobs, and in fact practically all forms of rotary cutters.

Furthermore, the object is to provide means for detachably securing the pattern so that the same may be removed at will and patterns of other designsor having different numbers and forms of teeth may be quickly and easily inserted.

The invention consists in the combination and arrangement of'partsset forth in the following specification and particularl pointed out in the claims.

Referring to the drawings:

Figure 1 is a plan view of a portion ofa lathe, including both spindles thereof and the tool support, together with the attachment embodying this invention, other portionsof said lathe being eliminated to save space. I

Fig. 2 is a side elevation of a finished cutter, illustrating one of the many forms which may be produced by means of the device.

Fig. 3 is a detail side elevation of the at tachment.

Fig. 4 is a section taken on the line 44 of Fig. 3.

Fig. 5 is a detail view of the connecting rod guiding member.

Fig. 6 is a detail sectional view of a pat tern and its operating collar, illustrating another method of detachably securing the pattern to the collar so that it may be quickly attached or detached in changing from one form of pattern to another.

Like numerals refer to like parts throughout the several views of the drawings.

In the drawings, 1 and 2 represent the spindles of a lathe. 3 is an arbor pivotally mounted upon the spindles 1 and 2 and in the present instance operated by means of .a dog 4 from the driving spindle of the lathe. This particular form of arbor and the manguide 7 is carried by a slide 8 which is mov- V able longitudinally of said. arbor upon a suitable guide 9. i A tool 10 is secured to the tool carrier 6 in the usual manner, that is by a tool post 11.

The invention in its preferred form embodies a collar 12 mounted upon the arbor 3 and secured theretopreferably by. means of a scr ew.13. Detachably secured to the collar 12 is a pattern 14 consisting of a plate or disk having a series of teeth 15 disposed in-its periphery. -The numberand contour of the teeth are substantially the same as the number and contour of the teeth to be re-v produced upon the work. This of course,

refers to the circumferential contour of said teeth butnot the longitudinal contour thereof. f

The pattern 14 is detachably secured to the collar 12 in the present form by means of screws 16. A follower17 is arraugedadjacent to the periphery of the pattern 14 vand is constructed in the form of a pin arranged parallel with the longitudinal axis of the arbor 3 and in contact with the teeth 15 of said pattern. The opposite ends of said pin project beyond the opposite faces of the pattern 14 and into recesses 18, 18 formedkin a pair of rings 19 and 20 arranged upon opposite sides of said pattern and preferably in I contact therewith.

The ring 19 has a central opening 21 substantially larger in diameter than the collar 12 and in fact large enough to permit a' movement of the r1ng 19 corresponding with V the shapeof the teeth of the pattern. The ring 20 also has a central opening 22'substantially the same size as the opening 21 and through this opening the arbor, 3 and the heads of the screws 16 project.

Between the rings 19 and 20 is arranged a third ring 23 which has a central. recess 24 within which the pattern 14 is arranged to rotate, said ring substantially fitting the outside diameter of said'patte'rn. A notch 25 is formed in said ring 23 to receive the follower 17 when said follower is in its outermost position with relation to the teeth of the pattern. V

Operatively connected with the follower 17 is a connecting rod 26 which transmits the movement of said follower 17 to the tool slide 6. The means for connectingthe rod to the follower 17 consists of a pin 27 disposed upon the opposite side of the arbor 3 from the. follower 17. Thispin-projects into recesses 28, 28 formed in the rings 19 and 20.

To maintain the connecting rod 26 radial with respect to the axis of the arbor 3 a bearing 29 for said rod has been provided on the ring 23. The two rings 19 and 20 are secured together preferably by means of screws 30 which extend from the ring 20 through slots 31, 31' in the ring 23 and have screw threaded engagement with the ring 19. The slots 31 are long enough to permit the rings 19 and 20 tomove eccentrically with the passing of each tooth of the pattern 14 by the follower 17 and during such movement the'connecting rod 26 will be reciprocated' in the guide or bearing 29.

Means have been provided for'moving'the follower 17 to the depth of each tooth15 during the rotation of said pattern. This means preferably consistsof a spring '32-arranged to encircle the rod 26 between the bearing 29 and collar 33 mounted upon said rod.

The end of the rod 26 is screw threaded at 34 and this end is adapted to be passed through a lug 35 formed upon a bracket 36 detachably secured to the tool slide 6 preferably by means of screws 37 and '38 so that said bracket may be adjustable longitudinally of said slide. The lug 35 has a'slot '39 into which the end 34: of said rod is placed, and permitted to be moved lengthwise of said lug in accordance with .the adjustment of the slide 8 on the guide 9 of the lathe so that the tool 10 may be properly alined with the work. 1

The collar 33 ofsaid rod is adapted to seat against one face of said lug 35 while a nut 40 is arranged upon the opposite side of said lug and has screw threaded engagement with said rod so as to impart movement to the tool slide through the bracket 36 and the lug 35 whenthe follower 17 is moved outwardly relatively to the axis of the arbor 3 by the teeth of the pattern. The end of the tool 10 is formed in accordance with the finished shape of the face .of the work and the same is moved into contact with the work 5 through the instrumentalities of the pattern 14; and the connecting means hereinbefore described.

In Fig. 6 I have illustrated a pattern member 41 attached to a collar 42 by means of a key 43 instead of by screws 16, as illustrated in the previously described form. The key 413 projects intoa slot in the member 41 and also into a slot. 4:4: formed in a sleeve 45 which projects from the collar 4L2 through the hole in the pattern 4:1. The collar .42 is secured to the arbor 3 by means of ascrew 46.

The operation oft-he attachment is as follows:

A pattern having the desired number of teeth is attached to the collar 12 as shown, this being accomplished by removing the screws 30 and rings 20 and then in removing the screws 16; and pattern 14 and replacing the same with the pattern desired.

A- blank constituting the work is placed upon the arbor as at 5, and the tool 10 having its end 7 formed to correspond with the finished face of the teeth to be cut upon said work, is adjusted properly with respect to the'face of said work and the lathe set into operation.

lfthe face'of said work is extremely wide it will be necessaryto first remove a very thin chip and before the work is entirely completed a number of rotations of the arbor 3will be necessary and at each rotation-the tool may be advanced according to the thickness'of the chip-to be-removed. Such an advancement of the tool may be accomplished either by rotating'the usual slide operating screw or by rotating the nut 40 on' the rod 34:,- thus advancing the slide 6,

together with the tool 1 0. This method provides a fine, accurate adjustment for the tool. The above description refers onlyto the app'licationof this invention to an arbor which is rotated while the tool is held stationary, but in so far as the invention itself is concerned the arbor might be held stationary and the tool rotated and operated equally as well. Y

Having thus specifically described my'invention what I claim and desire by Letters Patent to secure is: I

1. In a backing off device a pattern, a follower for said pattern, a rod connected with said follower-{a guide member for said rod, a ring adapted to surround said pattern in contact with'the periphery thereof and support said guide, and a spring adapted to maintain said follower in 'contactwith said pattern.

2. In a backing oif' device a pattern, a

lower'adapted to be moved thereby radially with respect to said pattern, a guide member for said rod having a portion arranged to encircle said pattern, and a spring encircling said rod and bearing against said guide member adapted to maintain said follower in contact with said pattern.

4. The combination of a pattern, a ring encircling said pattern and in contact with the periphery thereof, a follower for said pattern, a pair of rings mounted one upon each side of said follower and constituting supports for said follower, a tool carrier connecting rod connected with said carrier and with said rings, said rod having sliding engagement with said first named ring radially with respect to the axis of said pattern, means for rotating said pattern to impart movement to said tool carrier in one direction, and a spring adapted to maintain said follower in contact with said pattern and to move said tool carrier in the opposite direction.

5. The combination of a pattern, a follower for said pattern, supports for said follower arranged upon opposite sides of said pattern, a tool carrier, a connecting rod interposed between said follower supports and said tool carrier, a guide for said connecting rod, and a spring surrounding said rod adapted to yieldingly retain said follower in contact with said pattern.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

THEODORE MELDER. Witnesses:

SYDNEY E. TAFT, HATTIE E. STRATTON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G." 

